Bevel and hypoid gears can be cut in a single or intermittent indexing process (face milling) or in a continuous indexing process (face hobbing). A basic cutting setup in the generating or cradle plane will put the center of the cutter head in a position which is away from the generating gear center (cradle axis) by the amount of the so called radial distance. The silhouette of the cutter blades represents one tooth of the generating gear while the cutter rotates. Common face cutters for bevel gear cutting have several blade groups with each group having between one and four blades. The most common cutters are alternating (completing) cutters with one outside and one inside blade per blade group. In order to achieve an equal chip load of all inside blades and all outside blades during the cutting process, the cutting edges of all outside blades preferably follow each other at the same radial position. Also all inside blades should follow each other at the same radial position. In other words, all cutting edges of one kind (inside or outside) should generate the same cone surface while the cutter is rotating.
Manufacturing tolerances of the cutter head body, the blade blanks and deviations in blade profile grinding will introduce different cutting edge locations for the different blades in one cutter head.
While older face cutter systems allowed an adjustment of the radial blade position, today's stick blade systems have no provisions in order to accomplish a direct radial adjustment. However, known techniques which achieve a radial change of the cutting edge location include:    1. If a stick blade is moved in an axial position which is different from the nominal position, then the radius in the cutter reference plane increases or reduces by approximately ΔR=Δs·tan α, where Δs is a positive or negative axial movement of the stick blade and α is the blade pressure angle (for example, see U.S. Pat. No. 5,839,943).    2. If a stick blade is clamped with two clamp screws (upper and lower), then the increase of the torque of the upper or lower screw can move the blade tip slightly radially, if the stick blade is not exactly straight or if the normal slot wall is not exactly plane.
The disadvantage of the above Method 1 is that the blade tips of all axially shifted blades will be moved out of their common tip plane. While the blade adjustment improves the radial cutting edge location, it causes a runout of the blade tips. The blade tip runout will contribute to premature tip wear of the blades.
The disadvantage of the above Method 2 is that the cutter requires two clamp screws per blade and that the torque of those two clamp screws has to be chosen depending on the individual inaccuracy of blade and slot. It is also possible that due to the particular shape of blade and slot, no change in blade radius such as an increase of the blade radius or a reduction of the blade radius will occur. In such a case, an adjustment of this particular slot/blade combination might not be possible. Method 2 is based on coincidences which can only be controlled by time consuming trial and error loops.